This invention addresses the problem of the inhuman quality of metronomes. A metronome plays a central role in many devices besides a basic metronome. The function of a metronome is to provide a tempo, a series of audible or visual events with equal intervals of time between each event. The event could be the click or beep of a basic metronome. The events could be the underlying beat or tempo surrounded by a contraption of tones from a drum machine. The events could be slowed down in a guitar trainer, but the intervals of time between the events would still be equal. A metronome is a tempo generator.
The purpose of a basic metronome is to help musicians build confidence in their ability to keep a steady tempo. Tempo is the most critical quality of music. Unchanging intervals of time are necessary for musicians to stay in time together as they play music. A mistake in timing is so traumatic to music that it has been nick-named a “train wreck.” A steady tempo is also necessary for dancers to keep step with the musicians, or for musicians to keep step with a conductor. A conductor could be a robot, and the rhythmic motions of the robot's arms would be controlled by a metronome. The musicians could be robots and their rhythmic motions of banging on drums or bowing strings would be controlled by a metronome. Electronically, the tempo of the robotic conductor could be calibrated to the tempo of the robotic musicians and the timing of their performance would seem congruent or “tight”—that is, until human musicians attempted to accompany them. The humans would stumble often, falling behind the beat and catching up or getting ahead of the beat and waiting, swearing that the robots were not keeping a steady tempo.
This is the same problem musician's have with conventional metronomes. Robots and other embodiments of a metronome all suffer the same inhuman shortcoming. While a metronome is not necessarily a robot or a drum machine, a robot or a drum machine is necessarily a metronome. The metronome function is central and indispensable to their programming. The prior art rarely addresses the ‘unsteady tempo’ problem because the incongruity between the humans and the electronics is generally blamed on the humans rather than the mathematically-perfect, electronic metronomes. The result is a lot of frustrated musicians that are led to believe that they don't have good rhythm, and their metronomes sit unused because they don't want to be reminded of it. Conventional metronomes have failed, therefore, to fulfill their purpose of building confidence in the ability musicians have keeping a steady tempo.
Conventional metronome manufacturers do not recognize or appreciate that, because of biomechanical factors, humans are only capable of performing a limited number of tempos, and that these tempos are precise and the same for all humans. These specific, natural human tempos and the experiments used to identify them are disclosed in the Preferred Embodiment and Theory of Operation sections below. Conventional metronomes usually provide tempos of every whole number of beats per minute (BPM) within the musically interesting range of 40 BPM and 200 BPM. The metronome user cannot distinguish 115 BPM from 116 BPM, so some manufacturers limit the available BPM values by skipping some of the whole numbers. Still, this is done arbitrarily, with no appreciation of natural human tempo. Conventional metronome users soon find themselves chasing or waiting for the beat because the tempos are not calibrated to the internal tempos inherent to a human, and humans cannot change their biomechanical processes, such as refractory periods, so they compensate by jumping around, like a train about to crash.
The natural human tempos are a precise and discrete set of fast, “primary” tempos that humans prefer, unconsciously, when making rhythmic motions with their skeletal muscles, the muscles utilized in playing music and dancing. As data from the experiment demonstrates, slower natural tempos are perfect multiples of the faster natural tempos, suggesting that the fast natural tempos serve as basic units of duration that are counted, unconsciously, to form the “sense” of time. These natural human tempos were isolated and tested in a tapping experiment described in the Theory of Operation below. When converted from milliseconds to beats per minute, none of the natural human tempos were whole numbers of BPM. All conventional metronomes, drum machines and the like use whole numbers and only whole numbers of BPM, regardless of their range or choice of tempos. The natural human tempos have never been applied to an electronic device because they have not, until now, been discovered and appreciated or even forseen.
Unnatural tempos are the source of the frustration users have with conventional metronomes. Current science is teaching away from the significance of natural tempo. Richard Ivry is a prominent scientist in the field of human timing. Although Ivry recognizes that humans have biomechanical preferences, he states that “with equal proficiency humans can produce repetitive movements at any experimenter-defined rate.” (Ivry, R. B and Richardson, T., 2002, Temporal control and coordination: The multiple timer model. Brain and Cognition, 48, p. 119). The present research demonstrates that this is not true. Unnatural experimenter-defined rates still elicited significantly more responses from nearby natural rates or tempos. Tapping is indicative of timing throughout the body. Pickers, drummers, and dancers all use different body motions, but they still perform corresponding tempo. Therefore, if a musician could practice an unnatural tempo enough to perfect it and perform it on stage, no one would be able to dance to it. No author has ever suggested applying these biomechanical tempo preferences to a metronome, as evidenced by the lack of such technology.
Several devices are available which change the tempo of an incoming signal, like a guitar trainer. A guitar trainer slows down an incoming audio signal, from a CD for instance, but without changing the pitch of the music. The users then practice the guitar lick of choice at the slower tempo. Incrementally, the users then speed up the tempo to practice playing faster and faster until they can play the lick at full speed. Again, none of these devices, such as the audio signal processing apparatus in patent publication number US 2001/0042434 A1 from Yamada et al., show any appreciation for natural human tempo.
Attempts have been made to acquire more human-like tempos by the tap-tempo methods. These methods ostensibly allow the users to tap the BPM value they want to practice. Conventional metronomes, drum machines, and the like round these BPM values to whole numbers. Natural human tempos do not fall on whole numbers of BPM. Some tap-tempo methods, like the method in U.S. Pat. No. 6,812,394 to Weissflog, 2004 Nov. 2, take several taps and average them, which also produces inhuman BPM values. Some drum machines utilize an archive of live, human drum tracks. This feature attempts to solve the inhuman problem, but as soon as the users touch the tempo control knob the tempo is arbitrary again.
Here I would like to emphasize the significance that a fraction of a second can make in a metronome. Suppose a musician chooses to play a song at 130 BPM. A conventional metronome would click once about every 460 milliseconds. In practice, however, the musician spontaneously plays quarter notes every 440 milliseconds. Within 10 seconds, or 22 beats, the musician would already be leading the metronome by a full beat. This would happen eighteen times during a three-minute song. Unchecked, the musician would finish the song eight seconds before the metronome. The discrepancy would be noticed much sooner, though, and the musician would probably plug along, chasing and waiting for the beat. These compensations may or may not be conscious, but a natural tempo would still be more comfortable.
Other attempts have been made to bridge the gap between metronomes and humans. An apparatus from U.S. Pat. No. 6,230,047 issued to McHugh allows incoming music to change tempo according to the user's heartbeat. While a heartbeat is natural, it is by no means a tempo. Tempo is an indefinite and unchanging series of temporal events. The rate of a heartbeat changes constantly. Also, hearts are not controlled by the same nervous system as the skeletal muscles, so they do not abide by the same limitations, such as refractory periods. Moreover, there is no satisfaction in music corresponding to a heartbeat rate. The physical motions of exercise, like dancing, are more pleasant when entrained with the tempo of music. The heart rate has nothing to do with this relationship. In practice, this device could actually have the opposite effect rather than its intended effect. Running uphill, for instance, would make the heart rate accelerate. If the tempo of music was increased correspondingly, runners would be inclined to quicken their steps to match the music, rather than slowing down to save their heart. In any case, McHugh did not discover natural human tempo as described here. There is no discrete set of tempos or heart rates, for that matter, listed, and they would never be found by recording spontaneous heart rates.
Another attempt at “humanizing” a metronome also fell short of the mark. U.S. Pat. No. 4,380,185 describes a conventional metronome with the temporal events being the sound of a human voice. Apparently, Holcomb realized that a human counting off time before or during a musical performance does a much better job establishing and maintaining a tempo than metronome (Description of the Prior Art, pp. 4-5). Holcomb blames the incongruence of humans and conventional metronomes on time signature and beat pattern, however, not tempo selection. Holcomb clearly does not understand the origin of the incongruence. He misappropriated the advantage of the human voice to the sound of the human voice rather than the natural tempo of the human voice. Holcomb did not catalog the time between every syllable of hundreds of spoken sentences to find a discrete set of preferred cadences of speech. His selection of tempo is arbitrary, “variable between a minimum and maximum frequency” (claim 1 a, pg. 2). Claim 10 states that the human voice is a function of the selected tempo not that the selected tempo is a function of the human voice. Neither Holcomb nor McHugh utilizes, suggests or predicts a discrete series of tempos best suited for human use.
On National Public Radio, during the Here and Now program on Jan. 25, 2006, Evan Ziporyn discussed the problem he and his team from MIT had making music with robots more humanlike. Their robots could make minute incremental changes in tempo that humans could not perform or even perceive. Ziporyn made no indication, however, that limited human tempo capability was the stumbling block in the goals of their technology.